FirebaseMessaging 是 null null 和 SendMessage 因为它而失败

Question

我在这里有一个代码，我想使用 FireBase Admin 向 IOS 和 Android 发送推送通知。 我从方法中收到令牌、标题和正文。

var message = new FirebaseAdmin.Messaging.Message()
                {
                    Notification = new FirebaseAdmin.Messaging.Notification
                    {
                        Title = title,
                        Body = body
                    },
                    Token = DeviceToken.First(),
                    Apns = new ApnsConfig { Aps = new Aps { ContentAvailable = true, Sound = "default", Category = "test" } },
                    Android = new AndroidConfig { Notification = new AndroidNotification { ClickAction = "test" } }
                };

                var messaging = FirebaseMessaging.DefaultInstance;

                await messaging.SendAsync(message);